


Cycle Decoded

by toxic_virgo08



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: F/M, Ishigami village - Freeform, Kohasen, PMS, Senhaku, Senku x kohaku
Language: English
Status: Completed
Published: 2020-01-05
Updated: 2020-01-05
Packaged: 2021-02-27 14:28:30
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,490
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22128727
Author URL: https://archiveofourown.org/users/toxic_virgo08/pseuds/toxic_virgo08
Summary: Senku eases Kohaku's discomfort in a scientific way.
Relationships: Ishigami Senkuu/Kohaku
Comments: 13
Kudos: 137
Collections: Dr.Stone Stories





	Cycle Decoded

After returning from the oil exploration mission, Senku noticed a big acne perched atop Kohaku’s nose. He dismissed it, teenagers get it ten billion percent of the time. 

“You can take a rest while the others prepare for the provisions needed in our biggest project yet- going to the side of the earth where the petrification light started. There are tons of tasks delegated to everyone so basically everyone’s plate is full.”

“I can’t do that. I have to help anyone who needs assistance. And you said that everyone’s plate is full, might as well share the burden.” Kohaku crossed her arms in front of her chest taking on a defensive stance.

“Tch, such a gorilla! Where do you even get that unlimited strength?” Senku tried to convince her by goading her.

“I told you I’m not a gorilla!” Kohaku yelled at him, nerve appearing on her temple.

However, despite Kohaku flipping him off, he saw the exhaustion on her face as well as on Chrome’s and Ukyo’s faces. The trio travelled by foot after all.

“You know, taking is a rest is part of the job. How will you perform ten billion percent when your limbs are about to fall off from exhaustion, you lioness?”

“Well I’m not a lioness for nothing,” she smirked.

This banter did not go unnoticed by Yuzuriha. It’s been quite some time since she’s surrounded by lots of people. She wondered how the Ishigami villagers who were only used to seeing each others’ familiar faces are taking this new development on their daily lifestyle.

Yuzuriha is about to pass by the arguing duo on her way to the crafts room when Senku caught her attention. They stood a few steps away from Kohaku who remained rooted in her spot. They talked out of earshot while looking at Kohaku every now and then. Kohaku felt funny especially they kept on looking at her while Yuzuriha’s face was reddening a bit.

When it is apparent that Senku finished whatever he is telling Yuzuriha, Kohaku exclaimed, “I’ll enlist Ukyo’s help for that magnificent hearing he’s got and eavesdrop from even a hundred paces from you.”

“Oh, I’d like to see you try lioness. Later!” Senku waved and went to see updates on how the others are doing.

Before Kohaku has the chance for a witty retort, Yuzuriha led her by her arm.

“Kohaku, let’s go to the crafts room and take your measurement. We have plenty of cloth to work with after all.” Yuzuriha practically beamed and bounced her steps while dragging Kohaku. She can imagine different designs for Kohaku and she can’t wait for Kohaku to try them on like she did with Kinrou and Ruri.

Kohaku gave a bewildered look at Senku’s retreating back before following Yuruziha’s lead.

Inside the crafts room, Kohaku spotted different assortments of clothes, and cloths yet to be sewn into Yuzuriha’s beautiful creations. She saw a wood carved in the likeness of a human form in the corner. “Is this for target practicing?” she asked.

“Oh no, that’s a model for wearing clothes I designed. It’s called a mannequin.” Yuzuriha answered.

Yuzuriha measured the bust of Kohaku with a string. Kohaku sat there quizzically looking at dresses, clothes and a number of other clothing articles while Yuzuriha did wonders with her nimble fingers and agile hand movements. After a few nips, and stitches here and there, Yuzuriha handed her a small fabric.

“This is called a bra, and you clasp it here at the back, adjust the straps here and here so it fits snugly.” She explained to Kohaku, while showing how the straps work.

“Er, thank you, did Senku ask you to do this?” Kohaku asked after she changed into the article. She found that the texture and softness of the material somehow made her more comfortable than wearing what she was accustomed to use as animal skin for breast binds.

“Well he may or may not have,” Yuzuriha answered vaguely with a smile blossoming her face.

“Uhm, I have to talk to him again. Thanks for this Yuzuriha!” said Kohaku as she dashed off.

She found him talking to Gen, Chrome and a few other people from their generation who jumped ships from the Tsukasa Empire to the Kingdom of Science. She marvelled at how Senku’s charisma and manipulative stunts brought them the kind of manpower they need in order to bring back the glory of their lost civilization.

After Senku received updates with how their projects were moving along, Gen and Chrome left the two of them alone. She watched as Senku slumped on a chair and cracked his neck.

“You look tired,” she commented. She sauntered towards him and just stood by him.

He looked up only to see turquoise orbs meet his crimson ones.

“That’s rich coming from you.” He laughed. “We only moved 1 millimeter from where we started and there’s lots of work that need to be done. With that prospect, get excited!”

“Well, speaking of excited, did you ask Yuzuriha to make me this?” she asked as she gestured towards her chest.

“You don’t go around showing that to everyone, idiot!” Senku replied while looking away.

“No one’s interested 1mm of what you’re wearing.” He added while touching the back of his neck.

“Surely if you were the one making stuff, there has to be a scientific reason behind it right?” Kohaku prodded. She sat on the table with her arms crossed.

“You are a valuable ally of the Kingdom of Science and it won’t do if you’re not in your best element of ten billion percent.”

Kohaku stared at him with a big question mark written on her face.

“Why, what do you think is up with me Senku-sensei?” she asked.

“The past months I’m with you guys, it can’t be helped that I noticed. I pretty much know your cycle like the back of my hand,” Senku smirked.

Kohaku stood up abruptly, disbelief written all over her beautiful face. “You’re keeping tabs on my monthly cycle?”

“So as not to awaken the gorilla in you,” Senku in a low voice, “like now.”

“Hah! And how sure are you Senku, that you are correct?” Kohaku subconsciously took a step back.

“With your grumpiness level, I would say you’re having PMS right now.” Again that goofy smile.

“PMS?” Kohaku repeated.

“Premenstrual syndrome. You feel tired , irritable, bloated, you have acne and you’re feeling sore and tender breasts.”

As Senku rattled on the symptoms, Kohaku can’t help but agree for once with what Senku is saying.

“From when you got back, it seemed that your breasts grew bigger with the way the fabric of your dress was stretched more than usual. I figured, the increase in your estrogen caused your boobs to get bigger and progesterone made your milk ducts puff up making your breast feel tender and heavy. I asked Yuzuriha to make you a firm, supportive bra. You tend to move a lot and a good-fitting bra will help the pain associated with excess swaying of your breasts. And that’s why you feel grumpy is because of all the discomfort.”

“The what now? As usual, I don’t understand 1mm of what you’re blabbing on.” Kohaku deadpanned, though she did not miss the fact that Senku is looking at her. And he even knows her body clock at that!

“Bottom line is, it just means that your body is getting ready for a baby.” Senku stated matter of factly.

“WHAT!?” To Kohaku’s amazement, her fist connected to Senku’s face that put him in a much-needed sleep.

“Oops, that was a bit much,” she muttered to herself while she placed a sleeping Senku on his sleeping mat and covered his form with a blanket.

“Oh Kokahu-chan. Leaving already?” Gen greeted Kohaku as she was about to exit the crime scene.

“I might have accidentally knocked out someone to sleep,” was her sheepish reply.

After three days.

“Since every preparation for our numerous projects are well underway, we’re planning to go to the hotspring to gather some sulfur powder, would you like to come?” Chrome asked Kohaku.

The hike will take about a day by foot. The party consisted of Chrome, Senku, Suika, Ruri, Kohaku, Gen, Taiju and Yuzuriha. 

Chrome took the lead while Kohaku brought up the rear. With her abdominal cramps, she figured she could take it easy by walking slower. And there’s Senku whose physical stamina needs major overhaul.

Upon arriving, Kohaku wanted so badly to take a dip in the warm water but something held her back. Although the warm water looked inviting, she sat on a boulder satisfied to dip her thigh and her legs, keeping her center and the rest of her upper body out of the water.

The others did the same, they looked for spots that will keep them relaxed as they bask in the hot spring before they go on a long and arduous journey towards the source of the petrification light. Chrome and Senku are inspecting the rocks right off the bat. Taiju helped them position their tools before joining Yuzuriha at the hot spring.

Yuzuriha watched as Senku approached Kohaku. It is interesting indeed. She remembered how more than a year ago, the three of them were so desperate to escape Tsukasa. In the same place, Senku met his demise while practicing the one that he loves- science. But before that, she did not fail to notice how Senku discretely gave space to her and Taiju to talk privately. Senku wasn’t the odd one out in their group, he just felt he’s not one to be a romantic type. He is the intellectual who does not have time to fool around with feelings. Today however, she watched as Senku approached Kohaku who was sitting by herself and not taking a dip as the rest of the gang. Only Kohaku and Senku are not in their bathing wear.

“You managed to knock me off unconscious.” Senku told Kohaku.

“Are you mad that I made you sleep?,” she retorted.

“No, either way I couldn’t ignore my exhaustion button anymore, you just made it sooner.”

“You’re welcome,” Kohaku smiled. She splashed a little of the water running on her feet.

“Why don’t you take a full dip?” Kohaku asked Senku who made himself comfortable by claiming the seat beside her. 

“Why don’t you? Besides, I came here to collect sulfur powder.” Senku noticed how badly Kohaku wanted to jump in the water.

“You always think of work.” She stared at their party, how everyone loved the rejuvenating power of the warm water after hard days of work, apparent in their faces.

“It never hurts to be prepared. Especially a lot of the reagents were knocked off after the battle with Hyoga.”

“You know, I might take up Ukyo for his offer,” Kohaku visibly winced when the cramps in her abdomen demanded the pain to be felt.

“Why, what’s wrong?” Senku asked when he saw Kohaku grip her abdomen.

“The cramps in my abdomen are very uncomfortable “

“There is rose geranium oil back at the lab. You should use it when we get back. Suika collected the plants Pelargonium roseum. Gen and Chrome obtained the essential oil by hydrodistillation for three hours.”

Senku launched into a lengthy explanation of her anatomy and physiology, but seeing Senku in his best element does bring a smile to her face.

“The abdominal cramps are from prostaglandins which make your uterus contract helping to shed the endometrium out of your body.”

“You seem to know more about my body than I do.”

“I also know when your cycles are, mind you.” Senku said with that irritating smirk.

“What the hell?” A nerve found its way on her temple again.

“So what’s up with Ukyo?” Senku interrupted her before she get too violet and knock him down again.

“I think he’s good at mapping on the ground, he’ll be of tremendous help to the Kingdom of Science. I also wish to learn how he fully utilizes his hearing capabilities… ”

Senku’s mind wandered while Kohaku gushed about how amazing Ukyo is. He is brought to attention when Kohaku mentioned how Ukyo saved Chrome from falling when he caught Chrome with his arrow just when Hyuga and Tsukasa dealt him the killing blow.

“Care to repeat that again?”

“He said it will be totally okay for him to teach me archery. It will be so cool to fight from a distance,” Kohaku repeated while glancing at the spiky-haired man beside her.

“Is that right,” he said with a devious smirk.

“You look like a villain right now Senku. Stop making that face, you’re creeping me out.” She admonished him.

“All right, just stay put while I do this.”

Senku kneeled, balanced one of Kohaku’s legs above the water and perched it on his lap.

“Okay you’re freaking me out. I can still fight you know,” Kohaku threatened. She looked around and saw Ruri and Yuzuriha glanced their way, but they quickly averted their eyes when they caught her looking right back at them. It seemed like they were prying on such a private moment. Which isn’t because Senku is doing something weird again.

“Lo and behold the pelvic and menstrual busting powers of scientific knowledge.” Senku told her dramatically.

“There is a pressure point around your ankles called spleen 6.” He explained as his fingers located the inside of Kohaku’s left leg just above the highest point of her ankle. Then with four fingers width up her leg, he gently applied deep pressure behind her tibia (bone) and massaged the area for 4-5 seconds.

“This pressure point effectively alleviates pain and menstrual distress,” he said as he gently propped Kohaku’s leg down.

“Wow, so this pressure on my leg will trigger something in my gut?” Kohaku asked excitedly, eyes twinkling.

“Yes, and there’s a lot of pressure points that produce significant pain or other effects when manipulated properly.” Senku added.

While still on his knees, just before the sunset, the golden hour has approached. While everyone around them were soaking the healing power of the hot spring and minding their own business, Senku leaned over to Kohaku and she let out a small yelp from the sudden onslaught. When he finished, there is a small yet noticeable bruising on her neck from where Senku sucked on her skin. "What do you think you're doing?" She half-yelled, conscious of what the others would think if they were caught in that precarious situation. “This will help Ukyo mark out territories” his traditional smirk in place.

Unknown to them, Gen laid back and watched all of it unfold.

“Humans are such silly creatures. When they lose something they thought they had for sure, that’s when they stress and feel the most loss. Many psychological experiments have been conducted on this especially in love and relationships.”

“I never thought I’d see the day when Senku-chan experienced this himself.”

**Author's Note:**

> Thank you for reading!


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